More than 15 oil tankers linked to sanctioned oil shipments have switched their registration to the Russian flag within just two weeks. The sudden rise in reflagging activity has drawn attention across the global shipping and energy sectors. The data was identified in early January using maritime tracking and vessel registration records.
These tankers are part of a network often described as a “shadow fleet.” This fleet is used to transport oil from countries under international sanctions, including Russia, Iran, and Venezuela. The rapid move to reflag under Russia highlights how operators continue to adjust their methods to keep oil flowing despite restrictions.
A ship’s flag shows which country has legal authority over it. Changing a flag can affect how other countries respond to the vessel. By adopting the Russian flag, these tankers may be attempting to reduce the risk of inspections, seizures, or interference while carrying sanctioned oil.
Data Shows Sharp Rise in Russian-Flagged Sanctioned Tankers
According to data from Lloyd’s List Intelligence, more than 15 oil tankers linked to sanctioned oil were reflagged to Russia in a two-week period. This spike follows a broader trend seen toward the end of 2025.
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Figures from S&P Global Market Intelligence show that 25 tankers were switched to the Russian flag during the final quarter of 2025. Of these, 18 were reflagged in December alone. Sixteen of those vessels were already under sanctions from the United States or the United Kingdom when the changes took place.
Before moving to the Russian flag, many shadow fleet tankers sailed under smaller or less visible registries. These included countries such as Gabon and flags of convenience like Liberia. Some vessels were also found using registrations that appeared to be fake, linked to countries including East Timor and Malawi.
The shift toward the Russian flag marks a clear change in strategy. Instead of relying on obscure or lightly regulated registries, operators are now choosing a flag associated with a major global power. Shipping experts believe this move may be based on the assumption that enforcement actions could become more complicated or politically sensitive.
Legal Uncertainty and Enforcement Challenges at Sea
The legality of changing a vessel’s flag while it is at sea remains unclear under international maritime law. Normally, flag changes involve formal procedures and documentation, often completed while a ship is docked at a port. International rules do not clearly state whether mid-voyage reflagging is valid.
If a flag change is not legally recognized, a vessel could be considered stateless. Stateless ships have fewer protections under international law and may be boarded by foreign authorities. This legal gray area complicates enforcement decisions and can delay actions against sanctioned vessels.
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The issue has already affected real operations. In one recent case, the United States Coast Guard halted an effort to seize a sanctioned oil tanker after the vessel began displaying a Russian flag. The tanker, known as Bella 1, had remained outside Coast Guard control for nearly two weeks.
Officials believe the Russian flag was painted onto the ship’s hull to signal protection and discourage further action. Once the flag appeared, tracking and enforcement efforts became more complex.
Beyond reflagging, the shadow fleet continues to use other tactics to avoid oversight. These include changing ship names, altering ownership details, and manipulating location data. Some vessels turn off tracking systems or transmit misleading signals to hide their movements.
Together, these methods show how tanker networks transporting sanctioned oil continue to evolve. The recent surge in reflagging under Russia reflects an ongoing effort to operate within gaps in enforcement while moving oil from sanctioned sources.